STR/AFP/Getty Images(WASHINGTON) -- Three State Department officials have resigned after an internal investigation of the Benghazi consulate attack found “systemic failures and leadership deficiencies at senior levels in securing the compound,” prior to and during the assault, a U.S. official told ABC News.

Eric Boswell, the assistant secretary of state for diplomatic security, and Charlene Lamb, the deputy assistant secretary responsible for embassy security, as well as an official with the Bureau of Near East Affairs, resigned “under pressure,” the U.S. official said.

The report said that senior officials in the Diplomatic Security and Near East Affairs bureaus displayed management deficiencies that left security for the consulate, “inadequate for Benghazi and grossly inadequate to deal with the attack that took place.”

The Sept. 11, 2012, attack resulted in the deaths of four Americans, including the U.S. ambassador to Libya, Christopher Stevens.